[Influence of reagent evaporation on other laboratory reagents and appropriate countermeasures]

When the automated analyzer was first introduced, abnormally high values of urine creatinine and abnormally low values of serum creatinine were seen. It was shown that evaporation of the reducing agent stabilizer(sulfurous acid), which is present in the serum iron measurement kit, was occurring and that the observed low values of serum creatinine were due to consumption of hydrogen peroxide by gasifying sulfurous acid. After the cause was elucidated, the abnormal lowering of creatinine values was prevented. This experience demonstrates that care must be exercised when introducing new analytical method in clinical laboratories because evaporation of reagents can influence in other reagent systems.